Remote hoist control



N V- 1950 w. HARNISCHFEGER ET AL 2,529,804

REMOTE HOIST CONTROL 4 Sheets-Sheet 1 Filed April 27, 1946 INVENTORSATTO/P/VL X MQQQQ O 14, 1950 w. HARNISCHFEGER ETAL 2,529,804

REMOTE HOIST CONTROL Filed April 27, 1946 4 Sheets-Sheet 2 HOIST do QMBATTERY TEST W INENTORS Nov. 14, 1950 Filed April 27, '1946 W.HARNISCHFEGER ET AL REMOTE HOIST CONTROL 4 Sheets-Sheet 5 Alan/4% 1950w. HARNISCHFEGER ETAL 2,529,804

REMOTE HOIST CONTROL 4 Sheets-Sheet 4 Filed April 27, 1946 INVENTORSPatented Nov. 14, 1950 OFFICE REMOTE HOIST CONTROL Walter Harnischfeger,Milwaukee, and Glenn Koehler, Madison, Wis.

Application April 27, 1946, Serial No. 665,362

6 Claims. 1

This invention relates to cranes, hoists and lifting devices adapted tobe controlled from a distance and resides more specifically in anelectrically driven hoist adapted to be raised, lowered or stoppedthrough radiated impulses emitted by a portable control transmitterwhich may be carried to and operated at a point where a lift is to bemade or at any other location in the vicinity of the hoist.

Many power driven hoists particularly that form thereof known astraveling overhead cranes are employed in locations where large andirregular periods of idleness occur. In such instances it isuneconomical to maintain an operator in constant attendance and it isalso inconvenient for a temporary operator to have to climb to theoperators cab "each time it is neccesary to use the crane. To avoid thisdifficulty efforts have been made to employ pendant mechanical orelectrical control cords through which the crane maybe operated andcontrolled by a person situated on the floor who requires the servicesof the crane. For certain limited applications the pendant cord controlis quite serviceable, but where large obstructions either temporary orpermanent exist within the area served by the crane it is dangerous todepend upon pendant cord control. Also, with pendant cord control ratesof traversing of the trolley and bridge must be kept below that of awalk in order to permit the person operating the crane to keep up withpendant cord.

In accordance with this invention means are provided by which anoverhead crane may be controlled from any point on the floor by acontrol box or transmitter having no physical connection whatever withthe traveling parts of the crane. In this way the dangers introduced bypendant cord control are avoided, eificient speeds are rendered feasibleand the temporary operator need not climb to the control cab of thecrane in order to put the same in use.

This invention is herein described by reference to the accompanyingdrawings forming a part hereof and in which there is set forth by Way ofillustration and not of limitation one form in which the apparatus ofthis invention may be constructed.

In the drawings:

Fig. 1 is a circuit diagram of the receiving, control and power circuitsfor the three motors giving motion to the bridge, trolley and hoist ofan overhead crane;

Fig. 2 is a circuit diagram of a transmitting control circuit adapted toactivate the receiving control circuit of Fig. 1;

Fig. 3 is a front view in elevation of the transmitting control circuithousing; 7

Fig. 4 is a diagrammatic perspective view of the parts of one of theselector switch units which perform circuit selecting operations inresponse to received control pulses;

Fig. 5 is an end View in elevation of a remotely controllable crane withwhich the circuits and parts of the foregoing figures may be employed.

Fig. 6 is a circuit diagram of a control transmitter adapted for controlof a slightly difierent form of apparatus of this invention; and

Fig. 7 is a circuit diagram of a control receiver adapted to be actuatedby the control transmite ter of Fig. 6.

The form of the apparatus of this invention illustrated in the drawingscomprises, as shown in Fig. 5, a bridge or girder I mouted on end trucks2, arranged to travel on overhead runways 3. An electric driving motoror bridge motor 4 is mounted on the bridge I as shown and connected bytransmission shafting, not shown, and gearing 5 with the wheels of theend trucks 2 so as to propel the bridge in known manner. Secured to theupper faces of the bridge I are trolley tracks Ii, only one of which isshown, which support a trolley I in rolling engagement therewith.Trolley I is furnished with an electric trolley driving motor 8connected by gearing, not shown, with wheels of the trolley so as topropel the same upon the tracks 6 in known fashion. Also mounted on thetrolley 1 is the usual hoisting drum 9 from which hoisting line I0extends downwardly as shown. Drum 9 is arranged to be driven throughgearing, not shown, by an electric hoist motor II. Each of the motors 4,8 and I I are provided with brakes not shown which are automaticallyreleased upon admission of electric power to the motors andautomatically applied upon discontinuance of electric power admission inaccordance with well established practice.

For supply of electric power (in this case three phase alternatingcurrent) main trolley rails I2 and collector shoes I3 are provided atthe left end of the bridge I. Power mains not shown extend from theshoes to a control receiving unit I4 (to be described in greater detail)mounted near the right hand end of the bridge I from whence power isdistributed to motor 4 by leads not shown and to motor 8 by trolleywires I5, I6 and IT and to motor II by trolley wires I8, I9 and 2|] andby appropriate connections between '3 the respective motors, not shown,and the collector shoe assembly 2 I.

To complete the apparatus a portable control transmitting unit 22 (to bedescribed in greater detail) is provided which is capable of radiatingpulses to be received by control receiving unit It which will cause thestarting, stopping and reversing of the several motors 8 and II. Fromthis it may be seen that an operator may command the operations of thecrane through manipulation of the control transmitting unit 22 from anyconvenient location within the vicinity of the area served by the cranewith all of the advantages previously described.

The power and control receiving circuits of the crane and the controlreceiving unit [4 are shown in greater detail in Fig. 1 where thebridge, trolley and hoist motors i, 8 and Ii respectively arediagrammatically indicated. Within the control receiving unit It issituated a master maintainer receiver 23 so designated on the drawing.The receiver 23 is made up of a tuned loop antenna unit 24, a firststage of tuned radio frequency amplification 25, a second stage of tunedradio frequency amplification 26 and a hot cathode gaseous dischargetube and associated circuit 21.

To provide power for the operation of the receiver 23, a power pack unit28 having a transformer primary winding 34 is arranged to be suppliedwith current through lead 25 joined with main 1211, switch 3?), lead 3|,lead 52 and lead 33 joined with main 12b. Plate current for theamplifiers 25 and 26 is furnished by secondary winding 35 joined throughrectifier 36 and filter elements 37 to ground and plate current supplylead 38 as shown. Current for supply of the cathode heaters ofamplifiers 25 and 26 is supplied by secondary winding 39 as indicated.For heating of the filament of tube 21, secondary winding 53 isconnected as shown, while bias for the grid of tube 21 is created bysecondary winding 54. Bias for the grids of amplifiers 25 and 26 isprovided for through grounding of voltage divider resistor 55 shown at56. The output of amplifier 26 is applied to the grid of gas dischargetube 21 and when of sufficient intensity causes the tube 2'! to breakdown and become conducting completing a circuit from main 52a throughleads 29, 40, 4!, tube 27, lead 42, choke 43 and lead 44 to the coil ofsensitive relay 45 and thence through leads 46 and 47 back to main I21).Relay 45 is of the normally-open, delayed-release type being capable ofremaining closed for about one second after excitation ceases. Uponclosure of relay 45 a circuit is established extending from main 120,through lead 48, coil 49 of magnetic contactor master switch lead 5!],contacts of relay 45, lead 52 and thence through lead 4i back to maini2b. This causes the closure of master switch 5! and prepares the systemfor response to commands issued to it.

From the foregoing it will be understood that unless a nearly completelyuninterrupted signal of sufficient strength is continuously received bythe receiver 23 master switch 5| will not be closed and none of themotors 4i, 8 or H, supplied therethrough, can be operated. Receiver 23is tuned to a specific frequency, for example, 410 kc. or other suitablefrequency and is responsive to no other. Provision for its nearly steadyexcitation when needed by a signal of this frequency is made throughmeans contained within the control transmitting unit 22 to be more fullydescribed hereinafter.

For reception of commands directed to the hoist motor ll anotherreceiver generally designated 57 is also mounted in the controlreceiving unit I4. The receiver 57 in manner analogous to receiver 23 isprovided as shown with a tuned loop antenna unit 58, tuned radiofrequency amplifier units 59 and 50 and a hot cathode gaseous dischargetube ill and associated circuit elements. These parts are supplied withpower from the power pack 28 by connecting leads 38, Q! and 51 aspreviously described in the case of receiver 23.

The output of gaseous discharge tube 6| is confined to a circuitstarting with main l2a and passing through leads 40 and ii to thefilament of tube 6|. From thence the circuit passes to the plate of tubeti and then through lead 62, choke 53, lead 54, the two windings 55 and10 of step-by-step unit 65, leads 66 and 5'? and then through lead 47back to main l2b.

Receiver 5? is tuned to a specific frequency different from that ofreceiver 23, for example, 350 kc. or other suitable frequency and isresponsive to no other. Provision for excitation of receiver 51 inpulses of controlled frequency, spacing, duration and number is madethrough means contained within the control transmitting unit 22, to bemore fully described hereinafter.

Pulses delivered through the two windings B9 and it of step-by-step unit55, cause the sweep contact 58 thereof to be shifted to one or anotherof the three possible positions thereof as more fully indicated in Fig.4. As there shown the unit 55 comprises a pivotally mounted pawl supportll, normally held in the position shown, against the stop 72 by a springl3. Attached to the support ll intermediate the ends thereof by means ofan armature link 55 is an armature M positioned to be drawn into coil59- upon excitation thereof. At the lower end of support H a pawl 76 ispivotally attached and normally held in the position shown by a springll.

Located so as to be engaged by the pawl 76 upon its actuation by coil 59and armature M is that part of the toothed periphery of a ratchetsegment is which is designated l9 and which constitutes the drivingratchet of unit 65. Ratchet segment 78 is secured to a rotatable shaft36 normally held in and urged to return to the position shown by meansof a spiral return spring 8!.

For temporary retention of segment 18 and shaft 80 in any position towhich it may be advanced by the action of pawl 16 a pivotally mountedlocking pawl 32 having a spring retaining finger 83 is provided andmounted as shown to engage that part of the toothed periphery of segment'58 constituting the temporary retaining ratchet designated Attached tothe looking pawl 82Joy an armature link 84 is an armature 85 positionedwithin coil iii so as to be drawn to the left when the latter isexcited. To restrain immediate return of armature 85 and associatedparts under the influence of spring 85 when excitation of coil iii isterminated, pneumatic dash pct 87 is attached to the armature 85. Dashpotfl'l is provided with sufficient ventage or leakage between thepiston and cylinder wall thereof so that after an elapse of about 2seconds following termination of excitation of coil iii, spring 86 willhave taken charge to an extent necessary to cause disengagement offinger 83 from ratchet 83'. p g

By reason of. the structure of step-by-step unit 65 so far describedupon simultaneous excitation of windings 69 and 10 in pulses ofsufllcient intensity and spaced from one another by intervals less than2 seconds but more than the brief interval required for return movementof pawl 16, segment 18 and associated shaft 80 are advanced clockwise indiscrete steps against the action of spring 8|. As soon as properlyspaced pulses cease for a longer interval than 2 seconds segment 18 andshaft 80 are released'to return to normal position against the stop 88.The interval of 2 seconds is given by way of example only and may bemade longer or shorter as desired depending upon conditions to befulfilled.-

.Secured to the end of shaft 80 opposite the segment 18 is an armcarrying an advancing pin 89 and an arm carrying a clearing lever 90.Advancing pin 89 is so located axially with respect to radial followerpin 9I as to come into contact therewith and to rotate the same and theindependent sweep support shaft 92 upon which it is mounted whenevershaft 80 is sufficiently rotated. In like fashion clearing lever 90 isso positioned as to come into contact with and displace cam finger 93and final holding pawl 94 to which the cam finger 93 is secured.

The sweep supporting shaft 92 is separate from the shaft 80 androtatably mounted so as to carry the sweep contact arm 68 through an arcbringing the same into engagement with stationary step-by-step contacts95 and 96. A spiral spring 91 secured to the shaft 92 operates to returnthe shaft 92 and arm 68 to and hold them against the stop 98. Alsosecured to the shaft 92 is a holding segment having a toothed ratchetportion 99 positioned to be engaged by the tip of holding pawl 94, thetwo notches thereon corresponding to the two angular positions in whichsweep contact 68 is in contact with the stationary contacts 95 and 96.

In order to permit a single pulse series to produce either a netclockwise or counter-clockwise shifting of sweep contacts 68, advancingpin 89 and follower pin 9I are so related angularly, when the apparatusis in normal position, that 3 pulses or advancing steps of segment 18are necessary to bring them into engagement with one another. Alsoclearing lever 90 and cam finger 93 are so related angularly thatengagement thereof andrelease of holding segment 99 only takes placeduring movement of segment 18 from the second to the third step from thenormal or starting position thereof. By reason of this a pulse series ofless than .3 pulses will cause no change to take place in the positionof sweep contact 68. A pulse series of 3 pulses will not move sweepcontact if in the position shown in Fig. 4 or will cause it to bereturned thereto from' either of its other two possible positions. Apulse series of 4 pulses will cause return of sweep contact 68 from anyposition occupied by it to normal position and will then move it intocontact with stationary contact 95. In doing so clearing lever 99 passesbeyond cam finger 93 and to avoid release of holding pawl 94 duringreturn movement, clearing lever 90 is pivotally attached to the clearingarm at I 50 as to be free to lag by displacement of spring IOI duringreturn movement without displacement of cam finger 93' and holding pawl.94. In similar fashion a pulse series of 5 pulses will carry the sweepcontact 68 to and leave it in engagement with stationary contact 96regardless of the position occupied at the start of the'pulse series.

While a pulse series of more or less than 3 pulses may be employed as aclearing or preliminary pulse series by simply varying the number ofnotches or steps inthe segment 18 and appropriately relating the angularpositions of the other parts a three pulse clearing series is preferred.The reason for this preference is that the apparatus will ignore aspurious radiation having two accidental peaks spaced in a mannercorresponding to the delay interval necessary and will stop safe in therather improbable case of 3'such peaks being properly spaced. Theapparatus will only be dangerously responsive to the very improbablecoincidence of 4 or more such peaks occurring in properly spacedintervals. To provide a greater number of preliminary clearing steps isto introduce an undue lag in the response of the apparatus. To provide asmaller number is to unduly increase the possibility of response tospurious radiations.

Stationary contacts and 96 are employed as means by which selection ismade of either forward or reverse driving of the hoist motor II. To thisend contact 95 will complete a circuit from main I2b, through lead 41,lead 61, sweep contact 88, contact 95, coil of relay I02, lead I03, andlead I04 back to main I20. Relay I02 is of the normally-open,delayed-engagement type so that it will not respond to contacts madebetween contact 95 and sweep contact 68 when the latter is merelypassing to and from a position of engagement with contact 96. However,when contacts 68 and 95 remain in engagement for an appreciable intervalrelay I02 closes and completes a circuit from main I2c through lead I04,lead I05, the contacts of relay I02, lead I06 to coil I01 of switch I08and then through lead I09 back to power main I2a. This causes switch I08to close for forward driving of hoist motor II to cause a lifting motionof hoisting line I0. In similar fashion engagement of contacts 68 and 96causes closure of relay H0 and through lead III the energization of coilN2 of switch I08 to cause it to close for reverse or lowering driving ofthe hoist motor II.

When sweep contact 68 engages neither of the contacts 95 or 96 neitherof the coils I01 or H2 is energized and switch I08 remains open so thamotor II is stopped.

For control of the trolley motor 8 and the bridge motor 4 controlreceiving unit I4 also contains receivers H3 and H4 identical in make upwith receiver 51 with the exception that receivers H3 and H4 are tunedto respond, each to its own individual frequency. For example, receiverII3 may be tuned to respond to a frequency of 370 kc. and receiver I I4to a frequency of 390 kc.

By reason of the identity of circuit and of parts in the receivers 51,H3 and II4 detailed description of the latter two is unnecessary andseparate designating numerals for the parts thereof have therefor beenomitted to avoid unnecessary confusion. It is sufiicient to point outthat reversing switch I I5 under control of receiver II3 causes thestopping, starting and reversing of trolley motor 8 while reversingswitch I I6 in like manner responds to receiver II4 to control bridgemotor 4.

For excitation of receivers 23, 51, H3 and I I4 control transmittingunit 22 previously referred to is provided. The unit 22 as appears moreclearly in Figs. 2 and 3 is made up of a three element vacuum tube II6capable of driving an oscillating circuit with an output of limited Wattage. The plate of tube I I6 is connected by lead II1 with the midpointof a loop antenna II8 "7 which forms with capacitor I I Ban oscillatingcircuit'tuned'tothe frequency of the master main--.taiiner'receiver-'23.- Inductively related to the loop I I8' is-coil Iconnected to the grid of tube 116 so as to maintain oscillation. BatteryI2I "connected incircuitwith the filament of tube for heating-thesam'eis controlled by a switch or start stop button I22. For supply of platecurrentibattery I22 shuntedby condenser I22 is provided and connected asshown. Upon closure of start button I22 which is self maintaining ineither open or closed position antenna II8 begins to emit a steadyradiation at its tuned frequencyggiven for-example as 410 kc. If at thesame-time switch 38 in the control receiving unit I4"isclosed, masterswitch 5| promptly closes placing thecr'ane in readiness for use.

Connected as shown in Fig. 2 so as to augment the capacity of capacitorI it upon closure of dial switch I25'is a supplementary capacitor I26 ofsuch capacity as to alter the frequency of oscillation in antenna I I3to that of receiver I I4, for -=example, from 410 kc. to 390 kc. Dialswitch I25 is of conventionalconstruction and therefor showndiagrammatically only, being of the type which makes contact onreturn-movement only, which return movement is accomplished at aregulated rate. By reason of this a series of pulses of 390 kc.frequency is interposed in the steady emission of 410 kc. frequency eachtime dial switch I25 is actuated. Dial switch I25 is so adjusted as toits return rate that the duration of each of the 390 kc. pulses is lessthan the interval during which relay will maintain itself in closedposition. switch 5I isnot disturbed by any regular manipulation of dialswitch I25.

In like manner capacitor I21 is arranged to augment the capacity ofcapacitor IIQ upon actuation of dial switch I28 to such an extent as .toalter the transmitter frequency to that of receiver H3 while capacitorI29 will accomplish a similar function upon actuation of dial switch I32so as to alter the transmitter frequency to that of receiver 51.

For convenience there may be housed in the unit 22 a meter I3I forindicating the condition of batteries I2I and I23 upon closure ofbuttons I32 or I33 through connections not shown. A

meter IS I may also be provided for indicating plate current connectedin circuit in well know manner not shown.

It maybe observed that the relationship between transmitting unit 22'and receiving unit It is such that a command issued to the crane canremain under execution only so long as the transmitting unit 22 isproperly functioning. If .unit 22 fails from any cause receiver 23 is nolonger excited and master switch 5I drops open. .In this way it isimpossible for the crane to run away beyond the control of thetransmitting unit 22. V

In. operation a person intending to use the crane carries the unit 22 tothe location where supervision of the lift is most convenient. Switch3'0 is assumed to be closed. The operator then pushes the start buttonI22 and dials either north or south on dial switch I25 to bring thebridge I over'the lift. Before, after or during movement of the bridgethe operator may dial either east or west on the dial switch I28 tobring the trolley I to the desired position. Upon arrival of the bridgeI at the desired location "stop is dialed on switch I25 and upon arrivalof trolley I in the desired location stop By reason of this masterascgsoc is'dialed on the switch I33. Hoisting line I 6 at any timeeither before, during or after these motions-may be manipulated asdesired by similar dialing of switch I39. Lifting, traversing andlowering of the load is accomplished in similar fashion. At any time allfunctions of the crane can be brought to a stop simultaneously bypushing'the stop-button of switch I22. Upon again pushing thestart'button of switch I22 the crane will resume the execution of anypre-existing commands. v

In order to permit the clearing of pre-existing commands and to permitthe placement of suspended advance commands without activation ofreceiver 23 inductance I35 and mechanically interlocked switches I35 andI3? are provided and connected as shown in Fig; 2. When the latterswitches are moved from the position shown to a-position where I 36 andI3! are open, dial switches I25, I28 and I 36 may be actuated to movethe step-by-step units of their respective receivers H4, I I3 and 5? toand from any of their three positions but without any of these commandsbeing executed; When the switches I36 andIB'I are returned to theposition shown in Fig. 2 execution of any existing command will then bebrought about by reason of the activation of receiver 23. Itis preferredthat a single mechanical actua'tor for the interlocked switches ISG andI3! be'provided as shown at I38 in Fig. 3.

While the apparatus as above described is embodied in the familiar formof an overhead traveling crane having three functions or movements, itis evident that the apparatus may be adapted to cranes or hoists havingeither more or less than three functions. It also is feasible if desired7 to employ step-by-step units having more than three positions,controlled by appropriate dial switches in the transmitting unit 22, bywhich more than one forward or reverse driving speed may be selected.

In Figs. 6 and 7 is shown another form of the apparatus of thisinvention in which the control pulses are in the form of interruptionsin the otherwise continuously emitted radiation produced by the controltransmitter. As shown in Fig. 6 the control transmitter is made up ofthe 'threee lement tube I39 connected as shown in an oscillating circuitincluding an antenna I40 supplied by the plate current source MI througha dial switch M2. The dial switch I42 as shown is provided with aninterrupted contact ring I43 over which the self-returning contact armI44 may pass so as to cause interruptions in the plate circuit thusproducing interruptions in the emitted radiation. In normal position thearm I 44 remains in contact with the contact surface I43 as shown.Filament current is supplied from the sourceI I5 and is arranged to beinterrupted by the manual switch I45 when the apparatus is not in use.The signal emitted by the transmitter shown in Fig. 6 is adapted to bereceived by a receiver I tI having an antenna I23. The receiver I II maybe of well known form and so constructed as to close' the circuitbetween leads I 49 and I 50 so long as asignal is being received fromthe transmitter shown in Fig. 6 and in so doing to energize the relayI5I with current supplied through control-current supply leads I52 andI53. The'relay I5 I is-of the rapidly operating type and is biased by aspring I54 away from the position shown in Fig. 7 but is held in theposition there shown so long' as the transmitter 6 is emitting a signal.

Upon dialing of the switch I42 the several impulses in the form ofsignal interruptions which occur cause the relay I I to move from theposition shown in Fig. '7 to the position to which it is biased by thespring I54 and to return therefrom each time an interruption impulseoccurs. In the position shown in Fig. 7 contact I 55 of relay I5I beingjoined through lead I56 with control current supply lead I52 establishesa circuit through contact I51 and lead I58 with relay I59 and thencethrough lead I 60 back to control current supply lead I53. The relay I59is of the normally open, rapidly closing, delayed release type and itacts through its contacts and leads I6I and I62 to close and maintainthe closure of main power switch I63. When a pulse occurs and contactI55 leaves contact I51 momentarily, relay I59 remains undisturbedbecause of its delay characteristics thus maintaining the closure ofmain power switch I63.

The dropping of contact I55 due to an impulse also causes it tomomentarily engage contact I64 which through a lead I65 momentarilyenergizes relay I 66 which is provided with a return connection throughthe lead I60. The relay I66 is also of the normally open, rapidlyclosing, delayed release type the amount of delay being sufficient tooverlap at least two impulses caused by the contact arm I44 traveling atits normal rate. The closure of relay I66 is without immediate effectalthough a circuit from lead I60 through a relay I61, lead I68 and leadI69 is established in part up to a contact I 10. Upon termination of thefirst impulse contact I1I engages contact I10 thus completing thecircuit referred to by reason of connection of contact I1I with leadI56, the effect of which will be more fully described hereinafter.

During each impulse including the first the contact I1I also momentarilyengages the contact I12 but on the first impulse contact I12 connectedthrough lead I13 with contacts of relay I61 finds the relay I61 openand, therefore, perfforms no function. The relay I5I is provided with anadditional set of contacts I14, I15 and- I16 which likewise for reasonsto be more fully ex lained hereinafter are idle during the firstimpulse.

At the end of the first impulse re-closure of contacts I and I 51recharges relay I59 to insure maintenance of closure of main powerswitchI63. Also at the end of the first impulse contact I55 leaves contactI64, but relay I66 being of the delayed release type remains closedtemporarily. At the end of the first impulse also, contacts I1! and I1?)close thus completing the circuit which su plies relay I61 which thencloses. A single impulse such as this, however, does not operate to ca ue the execution of any control function which is felt by power elementsof the circuit to be more fully described and if but a single impulse isreceived, relays I66 and I61 will again open.

If a succession of two impulses is transmitted and received, as soon asthe second impulseinterruption starts relay I66 still under retention isrecharged but without effect since relay I6! is still. under retention.The closure of contact I1 with contact I12, however, brings into play anew circuit since the contacts of relay I61 are now closed causing relayI11 which also is of the normally open, rapidly closed, delayed releasetype to become energized and to close contacts I11A' and I11B. Closureof contact I 11B is without immediate effect since it is joinedby leadI18 with contact I15 which at the start of the impulse is open; Thefunction of contact I11B, however, is

.layed release characteristics of relay I11.

delayed, but briefly, since at the termination of the second impulsecontact I 15 is engaged by contact I14 with a result to be describedhereinafter. The closure of contact I11A, however, may be of immediateeffect since it is interposed in a circuit extending from supply leadI52 through leads I56 and I19 through a ratchet release magnet I andthence through lead I8I,

contact I11A, lead I82, contact I83, lead I84, clearing switch I andlead I86 back to supply lead I53.

Clearing switch I85 is a part of a stepper switch mechanism 236 having apivotally mounted control arm I 81 mounted on a shaft be attracted bythe magnet I88 previously re-' ferred to. If the contact arm I 61 isfound in any position other than that shown in Fig. '7 at the moment ofstarting of the second impulse switch I85 will be in closed position andthe closure of relay I11 will result in the energizing of magnet I80 andthe lifting of the retaining pawl I93 from the ratchet wheel I88 thuspermitting the spring I89 to cause return of the arm I81 to the positionshown in Fig. '7. By' reason of this any series of two pulses or thefirst two pulses of any series having a greater number of pulses thantwo will cause the arm I81 to return to the position shown in Fig. '1regardless of where the same may be located.

At the end of the second pulse interruption contact I55 engages contactI51 maintaining retention of relay I59 and continued' closure of switchI63. The separation of contact I55 from contact I64 is without immediateefiect because of the delayed release characteristics of relay I66. Atthe same time contact I1I re-engages contact I10 insuring retention ofrelay I61. The separation of contact I1I from contact I12 is withoutimmediate effect because of the de- The engagement of contact I14 withcontact I15 now sets up a circuit through lead I18, contact H113 andrelay I95 normally biased to the position shown which will be called theopen position which is of the quickly attracted, delayed release type.This closes contact [95A for a purpose to be hereinafter described andopens the contact I83 so as to permit the retaining pawl I93 to returnto retainingposition. On commencement of a third interruption impulserelays I59, I 61 and I95 maintain them selves temporarily while relaysI66 and I11 are recharged so as to prolong the maintenance thereof. As aresult all previously established circuits involving closure of therelays named are preserved and upon engagement of contact I14 withcontact I16 a circuit is established for the first time through leadI96, contact I95A, lead I91, advancing magnet I92, lead I98 and lead I60causing the advancing pawl I to move the arm I81 into contact with idlecontact I99. As the third interruption impulse comes to a close relaysI59, I61 and I are recharged to prolong the maintenance thereoftemporarily and relays I66 and. I11 become self-maintained 11;.temporarily thus. preserving. circuits previously setup. through; theserelays.

Ir-nofur-ther impulses occur, relays its. and H7. at the end of theirdelay period will drop open causing relays 16 i and i951- to follow atthe end. of their delay period; Thearmlti'i will thus-be leftin contactwith the idle contact 55353 Where it.v will remain: until 'anew pulseseries of at least two pulses is applied. to cause arm I811 torreturnrto the position. shown in Fig. '7.

In a pulse series of more than three pulses at the commencement of thefourth interruption pulse, engagement of contact Il' 'i with contact I76causes the motor magnet 52 to advance the-arm l8lto the segmentZilfi. Atthe end of the fourth interruption pulse contact arm it"? remains incontact. with segment are unless further pulses occur in the: series.For each pulse in the series in excess of four the arm I81. issuccessively. advanced to segments 25)! to 208, respectively, dependingupon the number of pulses in the series. Atthe termination of any pulseseries having more than two pulses contact arm 18? is leftin engagementwith that segment last contacted in the manner described in connectionwith the termination of a three pulse series.

The segments 26% to 298 are connected shown soas to control a hoistmotor 2%, a-

bridge motor 2m anda trolleymotor 2| i mounted as described inconnection with previously described formsof the invention so-as toactuate the. three essential motions of an overhead traveling crane. apulse series of sevenpulses willbring the arm I81 into engagementwithsegment: 293- and if the pulse series there terminates such. engagementwill be retained. In doing so a. circuit isestablished. through lead 2i2extending from control current supply lead E52 through spring I89 andarm [8? to segment 2G3 and thence through lead 2|3 to reversing switchmagnet- 2l4- and thence throughlead 2Hi-and the contacts 229 of relay215 to the lead- 2-H which joins with control current supply lead E53.Magnet- 214 is of the delayed attraction type so that it will notrespond to the passage ofarmit! across the segment 203- in movingto andfrom other segmentsbut only responds when the arm I8! is allowedto dwellfor a substantial interval in contact with segment 203. Upon sufficientenergization of magnet 2 Miorward driving contacts 2l8 are closed, thussupplying current.

from the power mains Zia-to the hoist motor 289 tocause the same totravel in the hoist direction. Atthe same time a maintaining contact 220is closed by energization of the magnet 2M thus providingfor maintenanceof the magnet 254 even though the arm I8? is subsequently. moved fromengagement with segment 2%. This maintaining circuit extends throughlead 22! and normally closed contact 222 and lead 223 into connectionwith control current supply main i52.' In entirely analogous fashionsegment 28 is connected through lead 22 5 with magnet 225 arranged toclose power contacts 226 to cause hoist motor 209 to travel in thelowering direction. Upon shifting of contact arm l8! from contact 283 to2ilt'the maintaining circuit of magnet 21 3 becomes broken by opening ofcontact 222. At the same time contact 22? closes to establish amaintaining circuit for magnet 225 which will cause it to re-- mainenergized even though the arm It] is subsequently moved out ofengagement with seg- In the casev of hoist motor 2t: 9

the-segment wills-required. to cause the magnet 2m to open the normallyclosed. contact 229 upon-which magnets225 and 2M. both depend.fortheirenergization. 'ilhusa four pulseseries will. cause stoppageiof.the hoist. motor 2694. re.--

garolless of. the direction iirwhich. it is traveling.

In-an entirely analogous mannera pulse series. of nine interruptionpulses will through. switch.

assembly 2-30 cause, driving of bridgemotor 21.0. in one direction whilea pulse seri-esof. tenpulses will cause driving of the same in theopposite direction throughv operation of. switch 23!. order: to. bringabout stoppagev of bridge motor 2H segmentzu-l andrelay 235are broughtinto.

play-bya pulse series-of five pulses. Similarly. through pulse seriesof- 11. or 12 pulses trolley motor 2-Hv can be. operated. in. eitherdirection.

through the operation. of switches. 232. and 233. stoppage of. trolley.travel. is brought about by a pulse seriesof six pulses. bringing intoopera.- tion.. segment202 and relay 234:

By. reason of the arrangement above described anqoperator. throughactuation of the transmitter. shown; inFig; 6 may dialso as;to bringintoplay ;;any. one or moreof. the cranefunctions which.

may all, proceed simultaneously. and v.may. at. any. time cause.stoppage. of. any of. such functions selectivelyor. in the-caseofemergencymay. cause stoppage simultaneouslyv of. all functions by open.-ing the manual. switch. M6.

in Fig. 6. shouldfailrelay I51 will move to the position opposite-that.shownin Fig. 7.. thus causing. main power. switch. Hi3v to open.Further- ;more, the apparatus of thisinventionas-set forth "in Figs.6-and4 '7 isrelatively. insensitiveto accidental transients since itwill not respond to.

cause any driving motion. of any motor unless a pulse. seriesv of at.least. five pulses shall. be. -impressed upon the receiverl i'l and itis very. unlikely that atransient will occur insuch a way as to. imitatesuch a five pulse series. Furthermore; in. the form of, apparatusdescribed. in

connection withFigs. 6 and. '7 but a single re- ..ceiver IA! isrequired, the structure. of which may be'substantially as shown inthe'caseof.

master maintainer receiver 2.3shown in'Fig. 1-

although any other. suitable form of. receiver.

may be used for the purpose.

We claim:

1. In a, remotely. controllable power unit a: transmitter adapted totransmit acontinuoussignal subject to. manually selected series ofpulse-interruptions of predetermined duration,..

spacing, and. number. ofpulses; an electricdr-iving motor for saidpower, unit; power mains for supplying power thereto; switch means insaid power mains. for establishing. and. interrupting,v

the supply of power to said motor; a receiver responsive. to the signal.transmitted by. said...

transmitter; means connected to-and activated by said receiverresponsive to the continuousv signal emitted. by said. transmitteradapted to. cause. closure of. said switch. means during per-.

, sistence of saidsignal. and toretainsaid switch.

Inv

It. is furthermore apparent that if. for any. reasonthetransmitter.

means closed thereafter for an interval not less than the duration of apulse-interruption of said continuous signal; selector means adapted tooccupy a plurality of selective positions, connected to said receiverand adapted to respond to a series of pulse-interruptions deliveredtherefrom to move to a predetermined selective position dependent uponthe number of pulse-interruptions in said pulse series; and means incircuit with said motor adapted to alter the operating condition thereofand adapted to respond to the position assumed by said selector means tointerpose a difierent operating condition upon said motor for eachselective position assumed by said selector means.

2. In a remotely controllable crane having a power unit for operationthereof a transmitter adapted to transmit a continuous signal subject tomanually selected series of pulse-interruptions of predeterminedduration, spacing, and number of pulses; an electric driving motor forsaid power unit; power mains for supplying power thereto; switch meansin said power mains for establishing and interrupting the supply ofpower tosaid motor; a receiver responsive to the signal transmitted bysaid transmitter; means connected to and activated by said receiver whenresponding to the continuous signal emitted by said transmitter adaptedto cause closure of said switch means during persistence of said signaland to retain said switch means closed thereafter for an interval notless than the duration of a pulse-interruption of said continuoussignal; selector means adapted to occupy a plurality of selectivepositions, connected to said receiver and adapted to respond theretoupon occurrence of a series of pulse-interruptions to move to apredetermined selective position dependent upon the number ofpulse-interruptions in said pulseseries; and means in circuit with saidmotor adapted to alter the operating condition thereof and adapted torespond to the position assumed by said selector means to interpose adifferent operating condition upon said motor for each selectiveposition assumed by said selector means.

3. In a remotely controllable crane having a power unit for operationthereof a transmitter adapted to transmit a continuouselectromagnetically radiated signal subject to manually selected seriesof pulse-interruptions of predetermined duration, spacing, and number ofpulses; electric driving motors for said power unit; power mains forsupplying power to said motors; switch means in said power mains forestablishing and interrupting the supply of power to said motors; areceiver responsive to the electromagnetically radiated signaltransmitted by said transmitter; means connected and activated by saidreceiver when responding to the continuous signal emitted by saidtransmitter adapted to cause closure of said switch means duringpersistence of said signal and to retain said switch means closedthereafter for an interval not less than the duration of apulse-interruption of said continuous signal; selector means adapted tooccupy a plurality of selective positions connected to said receiver andadapted to respond thereto upon occurrence of a series ofpulse-interruptions to move to a predetermined selective positiondependent upon the number of pulse-interruptions in said pulse series;and means in circuit with said motors adapted to alter the operatingconditions thereof and adapted to respond to the position assumed bysaid selector means to interpose different operating conditions uponsaid motors for each selective position assumed by said selector means.

4. In a remotely controllable power unit a transmitter adapted totransmit 'a continuous sigtacts and having a contact closed when saidsignal contact is closed said second relay being adapted to remainclosed for an interval not less than the duration of a pulseinterruption; a main power switch activated by said second relay contactadapted to close a power circuit to an operating unit as long as saidsecond relay contact is closed; a third relay in circuit with one ofsaid pulse contacts and having a contact which is closed when said pulsecontact is closed said third relay being adapted to remain closed for aninterval exceeding the spacing between pulse interruptions; a fourthrelay in circuit with another of said signal contacts and with thecontact of said third relay and having a contact which is closed whensaid signal contact is closed and said third relay is closed said fourthrelay being adapted to remain closed for an interval not less than apulse interruption; a fifth relay in circuit with the contact of saidfourth relay and with another of said pulse contacts and having aclearing contact and an advancing contact both of which are closed whensaid fourth relay is closed and said pulse contacts are closed saidfifth relay being adapted to remain closed for an interval exceeding thespacing between pulse interruptions; a sixth relay in circuit with theadvancing contact of said fifth relay and with the third signal contactadapted to be excited position; circuit connections adapted to completea circuit through the third of said pulse contacts,

the advancing contact of said sixth relay and the advancing magnet ofsaid selector switch; circuit connections adapted to complete a circuitwhen said selector switch is in a position away from home positionthrough the clearing contacts of said fifth and sixth relays and saidclearing magnet; a plurality of control circuits adapted to beselectively completed by said selector switch; and an operating unitconnected to be supplied with power through said main power switch andadapted to be controlled as to its operating condition by the selectiveaction of said selector switch upon said control circuits.

5 In a remotely controllable power unit a transmitter adapted totransmit a continuous signal subject to manually selected series ofinterruption pulses of predetermined duration, spacing, and number ofpulses; a receiver responsive to the signal transmitted by saidtransmitter; a receiver operated relay means; a main power switch 1activated by said relay means adapted to complete a power circuit to anoperatingflunitas long as a signal is being transmitted and received; aselector switch having means for selectively completing a plurality ofcircuits, an advancing magnet, retaining means and acleartngmagnet'adaptedto act upon said retaining means to cause saidselector switch to return to a home position; circuit connectionsbetween said relay means and said selector switch magnets adapted tocause said selector switch to move to complete predetermined circuits inresponse to series of predetermined numbers of pulse interruptions; aplurality of control circuits adapted to be selectively completed bysaid selector switch; and an operating unit connected to be suppliedwith power through said main power switch and adapted to be controlledas to its operating condition by said control circuits completed by saidselector switch.

6. Ina remotely controllable hoist having an electric motor for drivingthe same, a main power control switch for said motor, anelectro-magnetic radiation responsive receiver including switchoperating means operative to close said main power control switch uponexcitation, a second switch having a plurality of positionscorresponding to driving conditions of said motor in circuit with saidmotor, a second receiver including switch operating means operative toalter the position of said second switch upon excitation by apredetermined pulse radiation,

and a transmitter including means forming an oscillatable circuitcontaining an antenna, means for driving said oscillatable circuit tocause said antenna to emit a steady radiation capable of excitation ofsaid first receiver, and means adapted to interrupt said steadyradiation and to cause said antenna to emit control pulses of suchpre-determined spacing and duration as to excite said second receiver.

WALTER HARNISCHFEGER.

GLENN KOEHLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,188,202 Perry et al. June 20,1916 1,597,416 Mirick Aug. 24, 1926 1,635,779 Carter July 12, 19271,760,479 Colman May 27, 1930 1,805,167 Fitzgerald May 12, 19312,052,708 Hammond Sept. 1, 1936 2,325,829 Boswau Aug. 3, 1943 2,388,595Boyajian Nov. 6, 1945 2,388,748 Kipetzky Nov. 13, 1945 2,391,881 ClayJan. 1, 1946 2,393,892 De Ganahl Jan. 29, 1946 2,396,091 De Bey Mar. 5,1946 2,397,088 Clay Mar. 26, 1946 2,397,475 Dinga Apr. 2, 1946

